Arc-lamp.



G. M. LITTLE.

ARC LAMP.

APPLICATION FILED OCT. 3. 1913.

Patented May 28,1918.

2 SHEETS-SHEET I- ATTORNEY e. M.'L|TTLE, ARC LAMP.

APPLICATION FILED OCT. 3. i913.

1 ,268,025. Patented May 2s,191& A 2 SHEETS-SHEET 2- 2a Y 0;. i fi l Q 7 WITNESSES: IN ENTOR )QddW ATTORNEY STATES PATENT OFFICE.

GEORGE M. LITTLE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ARC-LAMP.

Specification of Letters Patent.

Patented May 28, 1918.

Application filed October 3, 1913. Serial No. 793,111.

To all whom it may concern:

Be it known that I, GEORGE M. LITTLE, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Arc- Lamps, of which the following is a specification.

My invention relates to are lamps, and it has particular reference to improvements in supporting and guiding means for the movable electrodes of such lamps.

Consumable electrodes, as furnished by manufacturers, usually have slightly varying diameters and, as a result, such electrodes, when used in the usual electrode holders affect the satisfactory operation of arc lamps. One of the above mentioned operating defects exists when an upper electrode, having a smaller diameter than nor mal, is held too loosely by its clutch, which results in the tilting of the electrode and,

consequently, in its binding a ainst the wall of the aperture through whlch it projects into the arc chamber. Another unsatisfactory operating characteristic of an arc lamp equipped with a usual form of clutching means for the upper electrode is that the upper electrode may be held out of vertical alinement with the lower electrode, thus causing an unequal consumption of the arcing end of the electrode and, consequently, an unsteady arc and a flickering light, by reason of the tendency of the arc to creep up the sides of the upper electrode. This defect is exaggerated when the upper electrode is of short length at the end of the trim.

One object of my invention is to provide a mechanism for an arc lamp which will retain the upper electrode at all times in vertical alinement with the lower electrode.

Ainother object of my invention is to provide a mechanism for an arc lamp which may be adapted to effectively hold electrodes, having variations in their diameters, and which will draw the same length of are at pick up.

My invention is illustrated in the accompanying drawings in which Figure 1 is a side elevation, partially in section, of the principal operating parts of a lamp constructed in accordance with my invention;

1; Fig. 8 is a front elevation of a clutching means embodying one form of my invention; Fig. 4 is a rear elevation of a portion of the device shown in Fig. 2, and Fig. 5 is a plan view of my electrode-engaging devlce.

Referring to the drawings, a movable upper electrode 1 cooperates with a lower stationary electrode 2 to maintain an are between the opposing ends. Inasmuch as the lower electrode 2 is stationary, the arc-regulating functions and feeding operation of the lamp must be performed in connection with the upper electrode 1. A clutching mechanism comprising an engaging member 4, which embraces the electrode 1, is pivotally connected to an armature 5 of U- shape which co-acts with feeding coils 6.

While the lamp is inoperative, the electrodes 1 and 2 are held out of contact and in substantially the positions shown in Fig. 1. When the lamp is connected to the supply circuit, the feeding coils 6 becoming energized, pull down the armature 5 and permit the electrode 1 to move into electrical contact with the electrode 2. When current flows through the two engaged electrodes, the circuit, comprising the windings of the feeding coils 6, is opened (by means not shown in the drawing), thereby releasing the armature 5. By reason of a tensional element or spring 7, to which the armature is connected, the electrode 1 is drawn away from the electrode 2 and an arc is established, the length of the arc being determined definitely by mechanical engagement between certain of the parts of my device, such mechanical engagement serving to limit the upward movement of the armature 5 and its associated parts. A dash pot 8, comprising a cylinder 9 and a piston member 10, is preferably inserted between the spring 7 and the armature 5, thereby preventing a too rapid separation of the electrodes when the coils 6 become deenergized.

A main supporting rod 11, which is suspended from the armature 5, extends through a guiding aperture 13 formed in the outwardly flanged portion 14 of a draft tube casing 15. The rod 11 is adjusted in parallelism relative to the axis of the upper electrode 1 by the proper positioning of the aperture 13 through which the lower portion of the rod 11 projects.

Upon the upper portion of the rod 11 is rigidly secured a sleeve 16 having an outwardly extending portion 17 that loosely embraces an auxiliary rod 18, to serve as a guide therefor.

Projecting through an opening 19 in the wall of the draft tube 15 and rigidly secured to the rod 18, is a member 21, of U-shape comprising two arms 22 that are spaced apart to permit insertion of the electrode 1 and to constitute the embracing member 4, substantially as shown in the drawing. A member 23, attached to the adjacent inner faces of the two arms 22 and formed to engage the electrode 1, terminates in a downwardly extending bifurcated portion 2 1 to which is pivotally secured an inclined lever member 25. The portion 2% is provided with an inward projection 21% having a horizontal surface 33. A gripping device 26 is rigidly connected to the member 25 and is shaped to extend in a substantially horizontal direction, when in operative position, as shown in Fig. 2, in which position the members 26 and 1 cooperate as an electrode clutch. The inner end of the device 26 is curved in wardly to conform to the contour of the electrode 1 during engagement therewith, the edge of the device being sufliciently sharp to firmly grip the electrode. For a View of the H'LGD'lbGl t engaging the electrode 1, reference may be had to Fig. 5. The lower end of the supporting rod 11 is provided with a longitudinally extending slot 27 which is bridged by a bearing roller 28. The free end 25 of the member 25 is supported upon and movably engages said bearing roller, substantially as shown.

With the upper electrode 1 in its raised position, a portion of its weight is transmitted by the rod 18 to the sleeve 16 which tends to cause the main supporting rod 11 to turn about its suspension point 29 to the left, as shown in Fig. 1, but the rod 11 is prevented from moving laterally by reason of the engagement of its lower end with the wall of the aperture 13. The vertical force exerted by the roller 28 against the member 25 causes the gripping member 26 to tend to rotate in a clockwise direction about the point at which it engages the electrode 1, and, consequently, the portion 2 1 tends to rotate about the same point and in the same direction. This causes the rod 18, by reason of its rigid relation to the portion 2 b, to tend to move away from the rod 11, but, in which tendency it is restricted to a limiting position in parallel with the rod 11 by the sleeve 16. There is thus a binding relation between the parts, so long as any weight of electrode exists, that maintains the rods 11 and 18 and the electrode 1 in parallel relation. This eliminates the tendency of the electrode to bind against the walls of an aperture 30 through which it projects into the arc chamracemes ber. Tn addition, the prevention of the binding of the electrode 1 in the aperture 30, and the assurance that the electrode 1 will burn evenly cooperate to insure satisfactory operation of an arc lamp embodying my invention. Electrodes having different diameters will be held firmly by the clutching mechanism, the rotation of the member 25 around its pivotal point of attachment to the member 2% serving to press the grip 26 against the engaged surface of the electrode before the upward movement of the electrode begins, irrespective of the diameter of the electrode.

The electrode 1 is intermittently fed, as in the usual type of arc lamps, and, in order that it may be released by the clutch to per mit it to feed into the arc, the armature 5 is drawn downwardly by energization of the coils 6. A surface 31 of the clutch member 1 engages a stationary trip 32. Thetrip 32 is disposed intermediate the projection 24: and the clutch member and is rigidly supported by a bracket 34- to a lower wall 35 of the draft tube casing 15.

Engagement of the clutch member 4 and the trip 32 disengages the gripping member 26 from the electrode 1 permitting the latter to fall into contact with the lower electrode 2, thus causing current to flow between the electrodes. This permits the armature 5 to rise to its normal position, carrying with it the rod 11., and tilting the member 25 around its pivot to grasp the electrode. When the electrode is grasped between the members 26 and 23, the electrode and the clutch member 1 begin an upward movement that is continued until the surface 33 of the clutch engages, the underside of the trip 32. l/Vhen the coils 6 are deenergized, the magnetic pull exerted upon the armature 5 is discontinued thereby permitting the spring element 7 to draw the armature 5 and the clutch mechanism attached thereto upwardly. Since the pull exerted by the spring element 7, at all times, tends to draw the armature upwardly a distance in excess of the proposed length of the are in addition to a length adequately compensating for the play between the cooperating elements, the surface 33 of the projection 24: will always effect contact with the lower surface of the trip member 32 when the armature 5 is released from the pull of the coils 6. In this position, the gripping member firmly. grips the electrode by reason of the pullexerted by the spring 7. By reason of the trip memberbeing stationary, the pull up of the lamp is substantially the same, thus insuring the production, at all times, of an arc of substantially uniform length with commercial electrodes.

While T have shown and described a paricular form of my invention, many changes may be effected therein without departing from the spirit and scope of the same, as set forth in the appended claims.

I claim as my invention:

1. An arc lamp comprising a central draft tube provided with a lateral'opening, a movable electrode positioned in said draft tube, an exterior main supporting rod, guiding means therefor, means for moving said rod longitudinally of said electrode, and a mechanism supported by said main rod that projects through the lateral opening in said draft tube to engage said electrode and impart motion thereto that is transmitted from said main rod.

2. An arc lamp comprising a central draft tube provided with a lateral opening, a movable electrode positioned in said draft tube, an exterior main supporting rod, guiding means therefor, means for moving said rod longitudinally of said electrode, a mechanism supported by said main rod that projects through the lateral opening in said draft tube to engage said electrode and impart motion thereto that is transmitted from said main rod, and means for limiting the upward travel of said electrode when engaged by the said mechanism.

3. An arc lamp comprising a central draft tube provided with a lateral opening, a movable electrode positioned in said draft tube, an exterior main supporting rod, that is constrained to move longitudinally, means for imparting motion to said main rod, and a mechanism that is supported by said main rod eXteriorly of the draft tube and projects through the lateral opening in the draft tube to grip said electrode, whereby the motion of the main rod may be transmitted to the electrode engaged by the said mechanism.

4. In an arc lamp, the combination with a movable electrode, of a clutch mechanism therefor comprising a main rod that is constrained to move longitudinally of said electrode, an electrode-engaging member supported by said main rod, an inclined lever member pivotally connected at one end to said electrode-engaging member and slidingly engaging said main rod and a gripping member attached to said inclined lever member for gripping said electrode when said main rod is moved upwardly, and a tripping mechanism for releasing the electrode when the said clutch mechanism is moved downwardly in excess of a predetermined amount.

5. In an arc lamp, the combination with a movable electrode, of a clutch mechanism therefor comprising a main rod that is constrained to move longitudinally of said electrode, an electrode-engaging member supported by said main rod, an inclined lever member pivotally connected at one end to said electrode-engaging member and slid ingly engaging said main rod, a gripping member attached to said inclined lever member, and means for eflecting a firm gripping action between said electrode and the gripping member when the former is moved upwardly a predetermined amount and for releasing said electrode from the gripping member when the electrode is moved downwardly a predetermined amount.

In testimony whereof, I have hereunto subscribed my name this 26th day of Sept, 1913.

GEORGE M. LITTLE. Witnesses B. B. Hmns, M. O. MERZ.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). G. 

